Happened to me once at KPHL. The heavies were all on 27L. We were sequencing to land on 35 behind a 757 landing to the west. Approach was talking to both of us continuously about our spacing. We needed a visual on the 75. We were never switched to tower for landing clearance even though we got good spacing for the crossover landing. Unbeknownst to us, tower was telling us to go around on tower frequency multiple times that we never heard. We continued and landed with no problem. Upon clearing the runway we learned we were still on approach frequency with no landing clearance. Two wrongs don't make a right. We got a phone number to call and I was worried that I was going to be reported. Turned out it was approach control apologizing for the unusual event. Nothing ever came of this. We all made mistakes that day.

My guess is the PNF preselected ground in the standby but accidentally line selected it to active making the tower standby. Probably trying to get ahead of the game once on the ground to limit heads down time. Its an easy thing to do on some equipment because thats your usual habit all the way across the country switching frequencies, you're continually line selecting it the active, but not preselecting.

If the AC crew had heard the repeated instructions to go around, they presumably would have done that, so let's say they didn't hear the calls. I realize that this assumes facts not yet in evidence, as an attorney might say, but if true, what would have been the proper procedure, especially if they suspected that they were having a radio problem due to silence during the approach? Also, how easy would it have been to miss the red light visual go-around signal from the tower? Lots of questions to be answered, but thankfully they landed without incident.

If they're focused on the runway approach lights, I doubt they would notice the handlight from the tower. They only look for that if they KNOW they have no COMMs (and squawking 7600). There is often silence for up to 2 minutes on tower frequency (can't speak for KSFO), but other busy airports where each runway has it's own tower frequency, would have windcheck, "..clear to land" and then "Monitor xxx.xx" after turnoff for each aircraft in separation.

In case the crew was completely focused on a flight deck issue, the tower should have changed his call to AC781. Droning the same thing over and over isn't going to break a crews focus if there was an issue.

In every part of the world except the US , when the Tower issued a landing clearance, it means exactly that. The runway is clear of traffic and you are “cleared to land”. In the US , Tower gives you landing clearance on first contact even though there may be preceding aircraft on approach or on the runway awaiting takeoff. What does FAA mean when an aircraft is “cleared to land”. If only the whole world can follow ICAO standards there would be no such problem.

I don't know what happened with ACA781's radios. I haven't heard or read a thing. Nothing has been reported. What happens in US airports, due to congestion, is they clear multiple aircraft to land on the same runway before any have touched down, while also clear aircraft to takeoff from the same runway and taxi aircraft across the same active. A zoo.

Most soundly managed airports with parallel runways dedicate one for outbound and the other for inbound. On this radio clip, the SFO Twr clears two inbound aircraft to land on 28R, ACA781 and UAL502. This rarely happens outside the US, for many good reasons.

There was no danger to ACA781. Whatever issue prompted the Twr to instruct a go around, like some aircraft wasn't where should've been, turned out to be a non-factor. Some people speculate that an AC pilot flipped the channel. Maybe. But the fact is, when a Twr issues a landing clearance, the Twr better be damn certain the runway is clear. In the US, due to too many aircraft, this doesn't happen. US Twr ATC landing clearances aren't any assured guarantee.

Maybe the ACA crew messed up, maybe they didn't. What's for certain is US airspace is a crap shoot.

In China any loss of comm of 10 minutes enroute or 3 minutes in the terminal area would result in severe actions against the pilots, including dismissal in the case of expatriate foreign pilots. As a safeguard we adopted a policy of NO OFFSIDE TUNING of the radio sets. Each frequency change must be done individually on the L and R sets and the PM must announce such changes It is hoped that such deliberate and conscious actions would reduce if not eliminate “finger problems”. Just another attempt ti reduce the chance of an accident, even if it means slightly more work.

Great observation. Some schools are training to have 4 presets. What if one of them changes? What if a pilot accidentally moves one into the active box? I teach in a glass cockpit and always mandate that every button or knob you touch needs to be confirmed either in the status bar (RNAV/GPS) or frequency box. Never make a change unless you confirm it.

Lots of comments! When we received a landing clearance, we were cleared to land unless some external thing appeared and our clearance was cancelled. We "never" changed radio freq. on the fly, never. However, ground freq. could have been preselected or tuned on another radio outside of the FAF. Things are changing but some of the basics still apply.

Could be incompetence, wrong freq. selected, distraction or whatever. The radio comms used by aircraft are grossly out of date old AM radio sets. One could easily have text messages sent by ATC to aircraft (voice to text so no typing by ATC) and displayed. One could have the flight plan auto-select the frequencies based on GPS position near airport. One could have single button acknowledge of receipt of ATC text message, and on and on. Text message stays displayed in aircraft until new one arrives. But the airline industry, while advanced in many areas, is running model T communications. I've read nothing about anything but ADSB, so I'm assumning old, out of date, unsafe comms will continue for some time.

I don't believe you. On final, maybe in the clag, your visual senses are close to MAX, even with autopilot, just making sure you're keeping the dirty side down and maximizing your odds for meeting the runway on centerline with room left for rollout and a stop. And you want to add reading ATC texts to that sensory mix? I'm a crusty old steam-gauge private pilot guy (SEL IFR) who puts a lot of credence in good old seat of the pants stick skills. Many of the recent commercial accidents appear to have been caused by piloting skills being superseded by systems management (or lack thereof) emphasis. If you're a pilot Allan, I'm a ballerina.

There are several radios in each aircraft each tuned to a different frequency anticipated to be handed off to as they change controllers. IT is possible the pilot not flying changed a radio earl once given permission to land. If a complete radio failure did happen the P/F would focus on flying the plane and make a visual approach while the NP/f would trouble shoot the problem.

If the P/F felt it was safe to land then he would land the plane, most likely in this event it would be the Captain taking command even if it had been the First Officer fling. If it was not safe to land and without radio communication it would be up to the tower and ATC Approach and departure control to clear air space as the pilot maneuvered for another approach. I believe this is all covered on the pilots approach and departure plates as to heading to fly and forth.

I couldn't see what was happening but judging from how he was handling other traffic on the ground, all of the fast-exits were blocked. I don't believe KSFO has a relief taxiway between 28L & 28R, so planes exiting off of 28R literally dead ends into the hold short line for 28L.

Sparkie, he expected that clearance and was specifically listening for it, not so with the GA instruction. Was the crew distracted? The CVR will answer that question. They definately missed many calls.

seems they "clear to land" miles out and when following other traffic... in my day we never "clear to land" until previous traffic on the ground and safely rolling off runway... they changed this years ago...

Tom,I agree. Landing at STL during an arrival block during VFR, the initial reply after checking in with tower was "expect landing clearance on short final". Once in a while there would be a another call from tower while on about a mile final to "expect landing clearance on VERY short final". Landing clearance was issued as soon as the nose gear left the ground on the departing jet on the same runway as we descended through 100'. They could move some traffic!

It is called anticipated separation. ATC gave up on "expect landing clearance on short final" because no one knows where "short final" is, and pilots with their butts clenched were going around (which they have every right to do) on their own and blowing the whole plan for the controller. It is much safer to clear the aircraft to land, and send it around if things don't work.

Of course, that assumes the pilots are listening.

Wonder what they were thinking: " Sure is quiet here at one of the busiest airports in the world......."

3−10−6. ANTICIPATING SEPARATIONa.Landing clearance to succeeding aircraft in alanding sequence need not be withheld if you observe the positions of the aircraft and determine thatprescribed runway separation will exist when theaircraft crosses the landing threshold. Issue trafficinformation to the succeeding aircraft if a precedingarrival has not been previously reported and whentraffic will be departing prior to their arrival.

With you re the "sure is quiet" comment. I'm guessing (as other commenters have here) that they dialed in Ground Freq but switched to it prematurely. But even then, they should have been suspicious hearing only taxi instructions while still on final, no? Whatever happened to "Bugsmasher 999, Home base tower, #4, cleared to land?"

Many questions to few answers. It is possible the radios failed right after receiving clearance to land or they may have changed to the ground frequency after receiving clearance to land. It may not be unusual to have changed to the ground frequency after receiving clearance but they should have been monitoring the tower on another radio. I hear it all the time when ground gives taxi instructions they will end with monitor tower on and give the frequency. This means stay with ground but listen for the tower on one of your other radios.

No sir you do not need to stay with ground. You switch to and monitor tower because that is the explicit instruction. Ground builds the sequence for tower and the tower will call you and issue takeoff clearance. The expectation at larger airports is that you will be ready for departure upon reaching the holdshort line. This is the norm at most Class B airports. It saves on limited frequency space not having every pilot call “ready for departure.”

Also, never anywhere is it normal practice to be on approach, call the tower, receive a landing clearance, and then switch to ground control. Many airports have multiple ground control frequencies, and you can never assume which frequency is in use at any particular time. Besides you don’t leave tower frequency on short final. That would dangerous. Stay with tower until instructed to do otherwise. ATCs are Air Traffic Controllers, not Air Traffic Suggesters.

I truly doubt that this is an Air Canada 'problem' It seems as though every airline gets their 'turn in the barrel', as I was informed when the Check Airman greeted me as he entered my cockpit. Over the past thirty-some years, American has been there, also Delta and United. I wouldn't get too excited.

In July an Air Canada Airbus 320 almost oanded on a taxiway in SFO missing 4 jets by less than 60 feet. It would have been one of the the worst aviation accident in the world. Read this article http://www.telegraph.co.uk/news/2017/08/03/pictured-moment-air-canada-jet-almost-caused-greatest-aviation/

The previous incident, another Air Canada almost landed on a TAXIWAY, NOT a RUNWAY, with 4 other fully loaded (Passenger and fuel) aircraft on it! The plane pulled up just 60 feet from one of the planes.....could've been the worst aviation incidents in HISTORY!

Lot ofs reasons for a go-around. Runway incursion from another aircraft, objects/vehicles on runway, animals, whatever. We don't need ATC if everything happens without any human or other failures in the chain of events.

So maybe part of the issue is “premature landing clearance”? I often wondered why I was often given landing clearance when I was number two on approach... in this case it bit everyone involved. A real sharp controller would have made the go around call on ground freq. guessing that the pilot had selected that frequency by mistake.I think most pilots leave the approach freq on the radio head in case a go around is required...I used to do that.

> "I would say this is quite a serious incident. Being asked multiple times to go around, and yet they continue to land."

This is a case of pilots rights vs controllers getting too big for their britches. This is yet another example of the FAA's foolish decision to call people who man the towers "controllers." Being labeled this way can cause an inflated sense of self with certain insecure people. They start thinking of themselves as "controllers" and before they know it they start trying to control everything around them, even aircraft on final approach as in this extreme case.

Pilots need to stick together and not let themselves be trampled upon by people with an inflated sense of power. The Air Canada pilots acted precisely as they should have, ignoring the person yammering at them on the radio. Such yammering is a threat to aircraft safety. Goog going AC!

Too often to count. However, after several repeats (if there's time, between other necessary instructions) usually, there is a response. It may be incorrect, and have to be corrected, but there is a response. All this in a dynamic environment. As someone else said, "Kudos to the controller" for remaining steady. Peace.

Are light gun signals no longer used by controllers in the Tower? Also, adding the reason for the go-around helps to emphasize the need for the go-around. But then, the pilot must be on the correct frequency.

"When the commands went unanswered, the traffic controller used a flashing red light gun to alert the crew to go around, which officials said is standard protocol for an unresponsive air crew. The move also failed to get the crew’s attention."

Maybe they can convert the PAPI or other visual indicator lights to flash red or something which will surely get the pilot's attention since the tower is not in the visual field of the pilots while on short approach.

Instead of telling an aircraft to "go around" six times with no reply, after the third time, I would have broadcast on all frequencies including guard and specify the exact flight and runway. I thought ATC had this capability. ATC has direct comm with all other agencies (ground, approach, departure) and can immediately advise them to attempt contact. This must not be in the controller's handbook. The FAA has their procedures and liability. They stick to it and watch an airplane land on an occupied runway saying "go around, go around, go around" until the crash. They did their job and that's the end of a day.

Have you seen or heard any of the CVR recordings of the taxiway incident? How could Air Canada management let them disappear? A management team dedicated to improving air safety would have preserved the recordings and used them as a learning tool to improve safety. The recording could also have been used to attempt to learn what happened in the cockpit of the Air Canada flight that came within less than 100 feet of a disaster to eclipse all disasters. Instead, management let the recording be recorded over and lost forever. Thus we know nothing of the taxiway incident. Pilots raised in this culture will also tend to ignore tower instructions.

Thinking ACA has an internal problem. Not the only time they’ve had an incident of being told to go around multiple times and failing to do so. Here a van entered the runway, ATC instructed twice to go around and they did not: https://youtu.be/EGVhfUBUvjc